If you apply to 1000 positions, but 700 are from those "zombie" job postings, then you've really only applied to 300 positions.
His approach was extremely different from how I would approach job applications though. The job he ended up getting was as a Ruby on Rails developer, as the 3rd person in a 3-person startup. And I don't think he knew Ruby when he applied, just html/css/js. And the job had him relocate to Ohio.
I think he's an extreme case, but I see "I applied to X-hundred jobs" posts so often that I do think it explains the massive applicant pools for most job listings.
I've never gotten a response from a job application where I put in very little effort though, so I can't vouch to whether it's a good strategy or not.